The purpose of the present study is to carry out a three year surveillance of the morbidity and mortality from cerebrovascular disease among the residents of the Leisure World retirement community in Laguna Hills, California. The information obtained from this survey will be related to data on precursors of stroke available from questionnaires completed in 1976 by approximately 11,000 persons or 65% of this population. Analyses of these two data files should provide valuable insights into the natural history of transient cerebral ischemic disease (TIA) as well as other risk factors of stroke. Useful information will also be obtained from this survey in regard to the value of such community-wide screening programs for the prevention of stroke.